1. Field of the Invention
This invention relates to protective coatings for microelectronic devices, more particularly to protective layers comprised of a monolayer.
2. Background of the Invention
Micromechanical devices typically comprise a device with moving parts manufactured with a size on the order of microns. Examples include gears, motors, moving mirrors and accelerometers. These moving parts sometimes come into contact with each other or with non-moving parts of the superstructure of the device.
Several techniques of lubrication and passivation are used to alleviate friction at these points of contact. The contact can cause physical damage to the parts, as well as sticking between the parts, preventing the devices from functioning as they are intended. Certain types of these devices, that contact other parts millions of times, have a problem with the lubricant or passivant desorbing from the surface. This leaves the surface unprotected and leads to damage.
Certain types of micromechanical devices are packaged with a passivant or lubricant contained in a hermetic package. The package must be hermetically sealed to prevent desorbed passivants from escaping the package. This allows the desorbed passivant to be replenished from within the package. These types of packages are expensive and require more complicated manufacturing processes.
Even without the package, however, the passivants or lubricants used in current practice desorb from the surfaces. A more stable passivant or lubricant is needed, preferably one that does not require a hermetic package.